import { useState } from 'react'
import { VARIABLES, CATEGORIES } from '../engine/variables.js'
import { PaletteCard } from './VariableCard.jsx'

export function VariablePalette({ workspaceVarIds, onAddVariable }) {
  const [search, setSearch] = useState('')
  const [collapsed, setCollapsed] = useState({})

  const toggleCategory = (cat) =>
    setCollapsed(prev => ({ ...prev, [cat]: !prev[cat] }))

  const q = search.toLowerCase()
  const filtered = (varIds) =>
    varIds.filter(id => {
      if (!q) return true
      const v = VARIABLES[id]
      return (
        v.name.toLowerCase().includes(q) ||
        v.symbol.toLowerCase().includes(q) ||
        v.id.toLowerCase().includes(q)
      )
    })

  // Group vars by category
  const byCategory = {}
  for (const [id, v] of Object.entries(VARIABLES)) {
    if (!byCategory[v.category]) byCategory[v.category] = []
    byCategory[v.category].push(id)
  }

  return (
    <aside className="flex flex-col h-full bg-slate-900 border-r border-slate-700 w-64 shrink-0">
      <div className="p-3 border-b border-slate-700">
        <h2 className="text-slate-300 font-semibold text-sm mb-2 tracking-wide uppercase">Variables</h2>
        <input
          type="text"
          value={search}
          onChange={e => setSearch(e.target.value)}
          placeholder="Search…"
          className="w-full bg-slate-800 border border-slate-600 rounded-md px-2 py-1.5 text-sm text-slate-200 placeholder-slate-500 outline-none focus:border-blue-500"
        />
      </div>
      <div className="flex-1 overflow-y-auto p-2 space-y-1">
        {CATEGORIES.map(cat => {
          const ids = filtered(byCategory[cat] ?? [])
          if (ids.length === 0) return null
          const isCollapsed = collapsed[cat]
          return (
            <div key={cat}>
              <button
                onClick={() => toggleCategory(cat)}
                className="w-full flex items-center justify-between px-2 py-1.5 rounded-md text-xs font-semibold text-slate-400 uppercase tracking-wider hover:text-slate-200 hover:bg-slate-800 transition-colors"
              >
                <span>{cat}</span>
                <span>{isCollapsed ? '▶' : '▼'}</span>
              </button>
              {!isCollapsed && (
                <div className="space-y-1 mt-1 ml-1">
                  {ids.map(id => (
                    <div
                      key={id}
                      onDoubleClick={() => !workspaceVarIds.includes(id) && onAddVariable(id)}
                      title={VARIABLES[id].description}
                    >
                      <PaletteCard varId={id} isInWorkspace={workspaceVarIds.includes(id)} />
                    </div>
                  ))}
                </div>
              )}
            </div>
          )
        })}
      </div>
      <div className="p-2 border-t border-slate-700 text-xs text-slate-500 text-center">
        Drag or double-click to add
      </div>
    </aside>
  )
}